Hydrogenolysis of polyhydric alcohols obtained from the natural world using a catalyst for converting the polyhydric alcohols into other compounds is an important technique from the viewpoint of effective utilization of materials or substances.
On the other hand, the amount of glycerol produced which is used as a polyhydric alcohol in food or medical applications has increased year by year. One of the reasons therefor is spread of bio-diesel fuels which have recently come to prevail owing to uncertain supply of fossil fuels or global warming problems. Glycerol is produced in the course of the process for production of the bio-diesel fuels from raw vegetable materials. However, excessive supply of the glycerol has occurred due to currently limited applications thereof. Therefore, effective utilization of the glycerol has been demanded. As one solution, catalytic reaction of the glycerol into C3 alcohols has been noticed over the world.
The C3 alcohols are useful as various industrial materials, etc. Among the C3 alcohols, there are 1,3-propanediol and 1,2-propanediol as diols. The 1,3-propanediol has been noticed as a raw material of polyesters and polyurethanes, etc.
On the other hand, the 1,2-propanediol has been used, for example, for production of polyester resins, paints, alkyd resins, various plasticizers, anti-freezing fluids, brake oils, etc., and further are useful for production of food wetting agents, viscosity enhancing agents for fruit juices, cellophane softeners for food, cosmetics, drugs, etc.
Hitherto, there have been known and proposed various methods for producing 1,2-propanediol (hereinafter occasionally referred to merely as “1,2-PD”) by hydrogenolysis of glycerol.
For example, as the hydrogenolysis using a catalyst, there are known (1) the method using a Ni—Re/C catalyst (for example, refer to Patent Document 1), (2) the method using a Ru/C catalyst (for example, refer to Patent Document 2), (3) the method using a Cu—Zn/Al2O3 catalyst (for example, refer to Patent Document 3), (4) the method using a Cu—ZnO catalyst (for example, refer to Patent Document 4), and (5) the method using a Cu—Cr catalyst (for example, refer to Non-Patent Document 1).
However, these methods are still unsatisfactory because of low conversion rate of glycerol, low selectivity to 1,2-PD, etc.
In addition, there are conventionally unknown any methods using a catalyst containing a copper component, an iron component and an aluminum component or a catalyst containing a copper component and a silicon component as a catalyst for hydrogenolysis of glycerol.
Patent Document 1: PCT Pamphlet WO 03/035582
Patent Document 2: EP 523014A
Patent Document 3: EP 523015A
Patent Document 4: DP 4302464A
Non-Patent Document 1: Applied Catalysis A: General, 281, 225, (2005)